Emergency Medical Services (EMS) Agency


Case Presentation:

Paramedics respond to an office building where a 49-year-old male is in cardiac arrest.  Co-workers called 9-1-1 when he clutched his chest and then suddenly slumped over a table in the lunch room.  A colleague moved the patient to the floor and began CPR soon after the patient collapsed. 

EMS arrives and continues chest compressions.  The patient is placed on high-flow oxygen with appropriate airway management and waveform capnography monitoring.  The patient is found to be in ventricular fibrillation (VF).

For a patient in VF, early defibrillation is the priority.  The patient should be treated in accordance with TP-1210, Cardiac Arrest.  He should be defibrillated immediately at 200J (or manufacturer equivalent).  Vascular access should be established.  Paramedics should place an intraosseous (IO) catheter if there is any delay in obtaining a peripheral IV.

Defibrillation should be performed immediately and repeated at each 2-minute cycle as indicated for a shockable rhythm.  Rhythm display technology allows for viewing the underlying rhythm without need for pulse checks.  A rise in end-tidal COwill signal ROSC. The first dose of epinephrine should be administered after the second defibrillation. 

Epinephrine has been associated with improved outcomes if given early in non-shockable rhythms, but early administration can worsen outcomes in shockable rhythms for whom treatment is immediate defibrillation.  Therefore, the first dose of epinephrine is given during the second cycle of CPR, after the second defibrillation for VF in accordance with American Heart Association guidelines.  This is in contrast to epinephrine administration for asystole/PEA (non-shockable) rhythms where epinephrine is administered as soon as an IV/IO is available.

Epinephrine (0.1mg/mL) 1mg (10mL) IV/IO can be repeated every 5 minutes for a total of 3 doses maximum, as per Los Angeles County EMS protocols.  Additional doses of epinephrine should only be administered in rare cases in discussion with the Base but are unlikely to result in improved survival.

The clinical benefit from administering epinephrine in cardiac arrest has been a topic of debate for many years and remains unclear.   Outcomes are demonstrated to be improved with early high-quality CPR and early defibrillation for shockable rhythms.  Most studies evaluating epinephrine administration in cardiac arrest have been observational.  Findings from these studies have suggested that epinephrine is associated with a significant increase in the likelihood of ROSC, but also a decrease in the likelihood of a favorable neurologic outcome, particularly with increasing doses1,2.

In 2018, results from the PARAMEDIC2 trial were published3.  This study, conducted in the United Kingdom, was a multicenter trial that randomized over 8000 patients to receive either epinephrine (1mg every 3 – 5 minutes) or placebo (no epinephrine during cardiac arrest).  The authors compared 30-day survival between the groups as a primary outcome.   Survival to hospital discharge and neurological outcomes at hospital discharge and at 3 months were among the secondary outcomes evaluated.  The study found that administration of epinephrine resulted in increased 30-day survival rates and survival to hospital discharge, but there was no difference in favorable neurologic outcome, with survivors in the epinephrine group being more likely to have severe neurologic impairment.

Other studies have shown that receiving less epinephrine is associated with better neurologic outcomes and that repeat doses of epinephrine (≥ 3 doses) is associated with decreased odds of survival4,5.

Based on these findings, the Los Angeles County EMS Agency, similar to many EMS systems, decided to limit out-of-hospital epinephrine administration in cardiac arrest to 3mg total.  Administering 3 doses of epinephrine provides for early administration of epinephrine when indicated, while limiting the doses in patients undergoing prolonged resuscitation, where epinephrine can begin to be harmful, and may increase survival with poor neurologic outcome.

Paramedics recognize VF and the patient is immediately defibrillated.  Vascular access is obtained via IO catheter.  The patient remains in VF after the second defibrillation attempt and epinephrine is administered.  Resuscitative efforts are continued and the patient remains in VF at the 18-minute rhythm check.   The patient has already received 3 doses of epinephrine for a total of 3mg (maximum total dose).  The last dose of epinephrine (0.1mg/mL) 1mg (10mL) IV/IO was administered 4 minutes ago.

The patient is in refractory VF (≥ 3 unsuccessful shocks).  It is recommended that patients in refractory VF have continued resuscitation on scene since they may have a good outcome despite prolonged resuscitation with continued high-quality CPR and the potential for early coronary angiography.  Underlying causes for VF include acute myocardial infarction, structural heart damage, electrolyte abnormalities, and cardiac conduction anomalies (e.g. prolonged QT interval).  Based on this patient’s history, an acute myocardial infarction is a likely underlying cause.  Given the possibility for favorable outcomes after prolonged resuscitation, patients with refractory VF should have continued resuscitation on scene for at least 40 minutes prior to transport to maximize the potential for ROSC in the field.  Exceptions would only be for cases that are transported early with mechanical CPR to an ECMO-capable center as part of an approved pilot study.

In this case, resuscitation should be continued with a focus on high quality CPR and defibrillation.  Routine additional dosing of epinephrine, beyond the 3mg maximum dose, is not recommended.  The Base can consider additional epinephrine dosing for patients in cardiac arrest with prolonged resuscitation on a case by case basis.  Reasons to consider additional epinephrine dosing may include conversion to or persistence of narrow pulseless electrical activity (which may represent profound shock rather than true electromechanical dissociation), or recurrent arrest.

High-quality CPR and defibrillation are continued.  Return of spontaneous circulation is achieved at 24 minutes.  Post-ROSC care including placement of an advanced airway, a 12-lead ECG, and treatment for hypotension with Normal Saline 1L IV/IO is administered.  Due to persistent hypotension, push-dose epinephrine is also initiated.

Paramedics obtain a 12-lead ECG that demonstrates ST-elevation in leads V1-V5 with reciprocal depression in inferior leads II, III, and aVF indicative of STEMI.  The STEMI Receiving Center (SRC) is notified and paramedics transmit the ECG.


Figure 1.  Acute Antero-septal ST-elevation myocardial infarction (STEMI)


The catheterization lab is pre-activated and the patient undergoes percutaneous coronary intervention (PCI) shortly after arrival to the hospital.  An occlusion of his left anterior descending (LAD) coronary artery is noted and a stent placed.  The patient has a favorable neurologic outcome and is discharged from the hospital with outpatient follow-up for cardiac rehabilitation.

  • Defibrillation is the priority intervention for shockable rhythms (ventricular fibrillation/pulseless ventricular tachycardia).
  • Early epinephrine is associated with improved outcomes in cardiac arrest (non-shockable rhythms).  Administration should not delay defibrillation in shockable rhythms.
  • Epinephrine administration in cardiac arrest is associated with improved rates of survival but not favorable neurologic outcome.
  • Routine dosing of epinephrine in cardiac arrest is limited to, Epinephrine (0.1mg/mL) 1mg (10mL) IV/IO every 5 minutes, maximum total dose 3mg in Los Angeles County.  If additional epinephrine doses are considered, it must be discussed with the Base prior to administration.
  • When considering additional doses of epinephrine, the Base should evaluate clinical circumstances on a case-by-case basis to determine if additional doses are warranted.


    1. Hagihara A, Hasegawa M, Abe T, et al. Prehospital Epinephrine Use and Survival Among Patients With Out-of-Hospital Cardiac Arrest. JAMA 2012;307:1161-8.
    2. Dumas F, Bougouin W, Geri G, et al. Is Epinephrine During Cardiac Arrest Associated With Worse Outcomes in Resuscitated Patients? J Am Coll Cardiol 2014;64:2360-7
    3. Perkins GD, Ji C, Deakin CD, et al. A Randomized Trial of Epinephrine in Out-of-Hospital Cardiac Arrest. N Engl J Med 2018;379:711-21.
    4. Kaji AH, Hanif AM, Bosson N, Ostermayer D, Niemann JT.  Predictors of Neurologic Outcome in Patients Resuscitated from Out-of-Hospital Cardiac Arrest Using Classification and Regression Tree Analysis.  Am J Cardiol. 2014 114(7):1024-8.
    5. Fothergill RT, Emmerson AC, Iyer R, Lazarus J, Whitbread M, Nolan JP, Deakin CD, Perkins GD. Repeated adrenaline doses and survival from an out-of-hospital cardiac arrest. Resuscitation. 2019 138:316-321.
    6. Anterior Myocardial Infarction. https://litfl.com/anterior-myocardial-infarction-ecg-library/ accessed 11/13/2019.

Author:  Dr. Denise Whitfield, MD, MBA